Add Marionette.deprecate

Resolves #1792.

We should talk about what we would like to deprecate in future. See: https://github.com/marionettejs/backbone.marionette/issues/1792#issuecomment-54090366
In that case I'd rather see Marionette.Error-style arguments:

```js
this.error = new Marionette.Error('message');
this.error = new Marionette.Error({
  message: 'My message.'
  name: 'Name',
  url: '/path/to/docs'
});
```

Also, I don't think we should reference an exact version number in the message.